AWS Interview Questions and Answers
Core services, IAM, networking, storage and cost-aware architecture.
Whether you are preparing for entry-level AWS interview questions for freshers or senior software engineer interview questions addressing concurrency, scalability, and system architecture, this track provides peer-reviewed model answers with syntax walkthroughs, edge cases, and practical interview tips.
1 How do you design a multi-region failover architecture on AWS? Hard
Design around an RTO and RPO first; they determine active-active versus active-passive.
- DNS and traffic: Route 53 health checks with failover or latency routing, plus Global Accelerator for TCP.
- Compute: deploy identical stacks in two or more regions using infrastructure as code, keeping services stateless where possible.
- Data is the hard part. DynamoDB global tables give multi-region writes, Aurora Global Database offers cross-region replicas with fast promotion, and S3 cross-region replication handles objects. A relational database with a single writer needs careful promotion.
- Messaging: replicate queues or use idempotent consumers.
Test with game days and chaos experiments. Watch for split-brain, replication lag, and cost. Active-active improves availability but multiplies spend and complexity; active-passive is cheaper but has a failover delay.
2 How would you troubleshoot high latency from an EC2 instance? Hard
Work from the outside in and use metrics before guessing.
- Confirm scope: is it the instance, the network, the application, or a dependency? Check CloudWatch CPU, network, and EBS metrics and the ALB target response time.
- Network: use VPC Flow Logs, check for packet loss, and test with ping, traceroute, or curl timing from a bastion.
- Instance: SSH in and run top, vmstat, iostat, and sar to see CPU steal, memory pressure, and disk I/O.
- EBS: burst-credit exhaustion on gp2 or throttled IOPS on gp3 shows as high await.
- Application: enable tracing, and inspect slow queries, thread pools, and GC pauses.
sudo iostat -x 1 5
sudo ss -s
curl -o /dev/null -s -w '%{time_total}\n' https://example.com
Right-size the instance, move to gp3, or fix the query. Check whether the bottleneck is a downstream dependency.
Frequently Asked Questions About AWS Interviews
What do hiring managers evaluate in AWS technical rounds?
Technical interviewers look for foundational fluency, idiomatic syntax, clarity when communicating complex logic, and awareness of performance trade-offs (e.g. memory footprint, render performance, and network latency) in production environments.
What are the best interview tips for practicing AWS questions?
Use active recall: summarize each answer in your own words before revealing the model solution. Focus on explaining why a certain approach is chosen rather than just memorizing code syntax.